U.S. patent number 3,924,027 [Application Number 05/401,552] was granted by the patent office on 1975-12-02 for process for the production of sensitized sheet material.
This patent grant is currently assigned to Kanzaki Paper Manufacturing Company Ltd., Sanko Chemical Company Ltd.. Invention is credited to Jujiro Kohno, Shinichi Oda, Toranosuke Saito, Daiichiro Tanaka.
United States Patent |
3,924,027 |
Saito , et al. |
December 2, 1975 |
Process for the production of sensitized sheet material
Abstract
A sensitized sheet for a pressure sensitive copy system is
obtained by coating the surface of a support with an acceptor
composition comprising a particulate mixture comprising an organic
acid substance selected from the group consisting of aromatic
carboxylic acids and polyvalent metal salts thereof, and an organic
high molecular compound. The above coating composition may further
contain an inorganic solid particle such as oxides, hydroxides and
carbonates of a polyvalent metal, and other mineral pigments. The
coating procedure may be carried out with use of coating means
mounted on the conventional paper machines.
Inventors: |
Saito; Toranosuke (Kobe,
JA), Kohno; Jujiro (Tokatsuki, JA), Tanaka;
Daiichiro (Arao, JA), Oda; Shinichi (Amagasaki,
JA) |
Assignee: |
Sanko Chemical Company Ltd.
(BOTH OF, JA)
Kanzaki Paper Manufacturing Company Ltd. (BOTH OF,
JA)
|
Family
ID: |
14192172 |
Appl.
No.: |
05/401,552 |
Filed: |
September 27, 1973 |
Foreign Application Priority Data
|
|
|
|
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Sep 17, 1972 [JA] |
|
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47-97430 |
|
Current U.S.
Class: |
427/147; 427/146;
427/150 |
Current CPC
Class: |
B41M
5/155 (20130101) |
Current International
Class: |
B41M
5/155 (20060101); B41M 005/00 () |
Field of
Search: |
;117/36.8,36.2,36.7
;427/147,150,146 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Herbert, Jr.; Thomas J.
Attorney, Agent or Firm: McGlew and Tuttle
Claims
We claim:
1. A process for the production of a sheet material for use in a
pressure-sensitive copy system which comprises applying on a
support sheet a suspension of a particulate mixture comprising (a)
100 parts by weight of an acidic organic substance selected from
the group consisting of aromatic carboxylic acids and polyvalent
metal salts thereof, and (b) from 5 - 300 parts by weight of an
organic high molecular compound selected from the group consisting
of polystyrene, styrene copolymers, .alpha.-methylstyrene polymer,
.alpha.-methylstyrene copolymers, polyvinyl chloride, vinylchloride
copolymers, vinylidenechloride copolymers, polychloroprene,
cyclopentadiene polymers, cyclopentadiene copolymers, acrylic ester
polymers, acrylic ester copolymers, acrylic acid copolymers,
methacrylic ester polymers, methacrylic ester copolymers,
methacrylic acid copolymers, vinylacetate polymers, vinylacetate
copolymers such as ethylene-vinylacetate copolymer, acrylonitrile
copolymers, acrylamide copolymers, allylalcohol copolymers,
benzylchloride polycondensation products, benzylchloride
copolycondensation products, meta-xylene-formaldehyde condensates,
diphenyl-formaldehyde condensates, and
diphenyl-metal-xylene-formaldehyde copolycondensation products,
said organic high molecular compound having a molecular weight of
at least 400 and a non-fluidic property at normal temperature and
being compatible with said acidic organic substance, and thereafter
drying.
2. Process for the production of sheet material according to claim
1, wherein said suspension further contains at least one of a
water-insoluble inorganic material, in form of particles, selected
from the group consisting of inorganic metal compounds and mineral
pigments.
3. Process for the production of sheet material according to claim
2, wherein said water-insoluble inorganic material is present in
mixture with the said particulate size.
4. process for the production of sheet material according to claim
2, wherein said water-insoluble inorganic material is present in a
weight ratio of from 1 to 10,000 parts to 100 parts of said organic
acidic substance.
5. Process for the production of sheet material according to claim
2, wherein said water-insoluble inorganic material is present in
mixture with the particulate mixture in a weight ratio of not more
than 2,000 parts to 100 parts of said organic acidic substance.
6. Process for the production of sheet material, according to claim
1, wherein said particulate mixture is obtained by mixing and
melting the organic acidic substance and organic high molecular
compound while heating, solidifying the resultant by cooling, and
then pulverizing it.
7. Process for the production of sheet material, according to claim
6, wherein said organic acidic substance and organic high molecular
compound are mixed and melted with a water-insoluble inorganic
material in form of particles while heating.
8. Process for the production of sheet material according to claim
1, wherein said particulate mixture is obtained by dissolving the
organic acidic substance and organic high molecular compound in an
organic solvent therefor and mixing same, evaporating the resultant
to dryness, and then pulverizing it.
9. Process for the production of sheet material according to claim
8, wherein said organic acidic substance and organic high molecular
compound are dissolved in the organic solvent with a
water-insoluble inorganic material in form of particles.
10. Process for the production of sheet material according to claim
1, wherein said particulate mixture is obtained by liquidizing the
organic acidic substance and organic high molecular compound by
heating or addition of an organic solvent, dispersing in water the
resultant, and cooling same or if necessary, removing the organic
solvent thereby obtaining a particulate mixture in water-dispersed
form.
11. Process for the production of sheet material according to claim
1, wherein said particulate mixture is obtained by mixing the
organic acidic substance, an initiator and regulator for
polymerization with a vinyl monomer capable of dissolving the
organic acidic substance, and effecting a suspension or emulsion
polymerization in water.
12. Process for the production of sheet material according to claim
1, wherein said particulate mixture is obtained by adding an alkali
metal salt or ammonium salt of aromatic carboxylic acid into an
emulsion or organic high molecular compounds, further adding a acid
or an aqueous solution of polyvalent metal salts thereto, and
effecting an acid decomposition or double decomposition thereby
obtaining a particulate mixture in water-emulsified form.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a sensitized sheet for use in a
pressure sensitive copy system and particularly relates to the
sensitized sheet having a coating comprising an acceptor which is
capable of color forming when coming into contact with a colorless
chromogenic compound.
Generally, the pressure sensitive copy system of the invention
utilizes a color forming reaction between an electron donating
colorless compound and an electron accepting solid acid.
Various types of pressure sensitive recording sheets are hitherto
known in the prior art. For example, U.S. Pat. No. 2,730,456
discloses a transfer type of the pressure sensitive recording
sheets wherein an upper sheet or overlying sheet is coated with a
layer containing micro-capsules in which an electron donating
colorless compound (hereinafter referred to as "color former")
dissolved in an oily solvent is enveloped, and an underlying sheet
is sensitized with a coating layer containing an electron accepting
solid acid (hereinafter referred to as "acceptor"). The color
former transfers into the underlying sheet upon rupture of the
micro-capsules and forms a visible colored image on the underlying
sheet. If multiple copies are desired, an intermediate sheet
carrying the micro-capsules on one side and the acceptor on the
other side is inserted between the upper sheet and the underlying
sheet.
Also, U.S. Pat. No. 2,730,457 discloses a recording sheet wherein
both of the fine capsules and acceptor are coated on the same side,
so called "self contained copying sheet".
Furthermore, German Pat. No. 1,275,550 discloses a pressure
sensitive recording sheet wherein a record forming components
soluble in a liquid solvent is carried on the surface and/or inside
of a support and said solvent is present isolated from at least one
of said record forming components by pressure-rupturable
capsules.
Examples of the color former include Leuco type of chromogenic
compounds such as Crystal Violet Lactone, Benzoyl Leucomethylene
Blue, Malachite Green Lactone, Rhodamine B Lactone, fluoran
derivatives and spiropyranes.
Known acceptors include acid clay, activated clay, attapulgite,
kaolin and other inorganic solid acids, but there are disadvantages
that a developed color image is faded by the action of moisture and
sunlight. A sensitive sheet coated with organic solid acid such as
phenolic resins is also used. However, such a sheet is apt to
yellow by the sunlight and the developed color image is decreased
in density or allowed to disappear for a little while by heat or
moisture.
As another example of the organic solid acid, aromatic carboxylic
acids (U.S. Pat. Nos. 3,322,557 and 3,488,207) and polyvalent metal
salts of aromatic carboxylic acid (DT-OS 2,152,765) are proposed.
There are, for example, described benzoic acid, o-nitrobenzoic
acid, o-chlorobenzoic acid, 4-methyl-3-nitrobenzoic acid,
p-isopropylbenzoic acid, p-tert.-butylbenzoic acid, salicylic acid,
5-tert.-butylsalicylic acid, 3-cyclohexylsalicylic acid,
3-methyl-5-isoamylsalicylic acid, 3,5-dinitrosalicylic acid,
1-naphthoic acid, 1-hydroxy-2-naphthoic acid,
5,5'-methylen-disalicylic acid and the other similar aromatic
carboxylic acids, and salts of metals such as magnesium, calcium,
zinc, cadmium, aluminum, gallium, tin, lead, chromium, molybdenum,
manganese, cobalt and nickel with the above carboxylic acids. Such
aromatic carboxylic acids and polyvalent metal salts thereof are
superior in stability toward the sunlight to the phenolic resins.
Some of the aromatic carboxylic acids and polyvalent metal salts
thereof have a sublimating property, and therefore a sheet
sensitized by a coating containing such acceptors loses a
color-forming ability with the lapse of time. Since the said
acceptors are relatively soluble in water and thus diffuse within
the sheet by the action of high moisture or water, the
color-forming ability is lost on the surface of the sheet. Such
disadvantages show an increasing tendency as the molecular weight
of aromatic carboxylic acid is lowered. The reason why salicylic
acid was formerly proposed but not used in practice is that it has
disadvantages as mentioned above as well as a weak point of lower
color density. Some of aromatic carboxylic acids and polyvalent
metal salts thereof show improved resistance toward heat and
moisture as the molecular weight increases and can maintain
relatively stable color-forming properties at normal temperature
and humidity. The pressure sensitive recording papers, however,
leave room for further improvements of the properties to be
required in practice. It is unavoidable that the recording papers
are stored and handled under the condition of high humidity or
water attaches directly to the sheet. For example, it often occurs
that rainwater or water spilt from a glass attaches to the sheet.
In some cases, when a letter or figure is printed by offset
printing on the upper or underlying sheet of pressure sensitive
recording papers, fountain solution on the blanket transfers onto
an acceptor coated surface of the sheet. Under such circumstance,
if an organic acid substance has insufficient resistance toward
high moisture or water, a sensitized sheet is markedly reduced in
the color-forming ability or in case the sensitized sheet is in
touch with a sheet carrying the encapsulated color former the
organic acid substance comes into contact with the color former by
means of the moisture or water as a carrier and thus there arises
undesirable color which is so called "smudge".
Accordingly, a coating layer containing the acceptor must have a
high humidity or water resistance sufficient to maintain
stabilities of the color-forming ability and developed color image
and to inhibit the "smudge".
On the other hand, a coating composition containing aromatic
carboxylic acids and polyvalent metal salts thereof, because of
being unstable toward heat in general, needs a careful watch and
handling during storage or coating procedure. Particularly, in the
coating procedure the coating composition is subject to mechanical
shear and accompanied by a rising temperature. Therefore, when a
mechanical and thermal stability is insufficient, the coating
composition cannot form a uniform layer on the surface of a base
sheet and in the worst case it is unavoidable to discontinue the
coating procedure. If the coating procedure is effected by a
coating apparatus mounted on a paper machine, it is the most
simplified process and therefore advantageous economically. In this
case since the coating composition is coated on the base sheet
preheated by a dryer, the mechanical and thermal stability
requirements become more severe.
SUMMARY OF THE INVENTION
It is, therefore, an object of this invention to provide a
sensitized sheet for a pressure sensitive copy system having
excellent resistance toward heat, light and particularly a high
humidity or water and capable of maintaining a stable color-forming
ability.
It is another object of this invention to provide acceptor coating
composition having an excellent mechanical and thermal
stability.
It is still another object of this invention to provide a process
for the preparation of a sensitized sheet in the most effective
way.
Other objects and advantages of this application will appear from
the detailed description to follow.
The foregoing and other objects of this invention are attained in a
sensitized sheet, for use in a pressure sensitive copy system,
having a coating comprising an acceptor, the acceptor being a
particulate mixture of (a) an organic acid substance selected from
the group consisting of aromatic carboxylic acids and polyvalent
metal salts thereof, and (b) an organic high molecular
compound.
The mixture of the organic acid substance and organic high
molecular compound can be pulverized to uniform fine powders of
several microns in particle size by mechanical means, for example
ball-milling. A coating layer having the fine powders homogeneously
dispersed therein is obtained and therefore the distinct images are
obtained.
DETAILED DESCRIPTION OF THE INVENTION
The organic acid substance to be used in the invention is selected
from the group consisting of aromatic carboxylic acids and
polyvalent metal salts thereof. The aromatic carboxylic acids and
polyvalent metal salts thereof useful for the acceptor are in
detail explained in U.S. Pat. application Ser. No. 265,484, filed
June 23, 1972, now abandoned, which discloses the pressure
sensitive record system. These compounds are illustrated by
non-limitative examples as given hereunder, but it should of course
be understood that other aromatic carboxylic acids and polyvalent
metal salts thereof, capable of color forming when brought into
contact with a color former may be also used.
An aromatic carboxylic acid to be used is represented by the
formula I, ##SPC1##
wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 each
represents hydrogen, halogen or a hydroxyl, amino, carboxyl,
carbamoyl, N-substituted carbamoyl, alkyl, cycloalkyl, alkoxyl,
aryloxy, aralkyl or alkylaryl group, and any adjacent pair of
R.sub.1 to R.sub.5 can, together with the carbon atoms to which
they are attached, complete a ring. Compounds of formula I wherein
R.sub.1 or R.sub.5 is a hydroxyl group are especially important in
embodiments of the invention as mentioned in detail
hereinafter.
Examples of aromatic carboxylic acids of formula I wherein R.sub.1
and R.sub.5 are not a hydroxyl group include benzoic acid, o-toluic
acid, m-toluic acid, p-toluic acid, p-tert.-butylbenzoic acid,
o-chlorobenzoic acid, m-chlorobenzoic acid, p-chlorobenzoic acid,
dichlorobenzoic acid, trichlorobenzoic acid, tetrachlorobenzoic
acid, phthalic acid, isophthalic acid, terephthalic acid,
2-carboxybiphenol, p-oxybenzoic acid, paramethoxybenzoic acid,
p-butoxybenzoic acid, p-octoxybenzoic acid, gallic acid,
anthranilic acid, phthalic acid monoamide, phthalic acid
monoanilide, 3-tert.-butyl-4-hydroxybenzoic acid,
3-cyclohexyl-4-hydroxybenzoic acid, 3-phenyl-4-hydroxybenzoic acid,
3-(.alpha.-methylbenzyl)-4-hydroxybenzoic acid,
3,5-dimethyl-4-hydroxybenzoic acid, trimellitic acid, pyromellitic
acid, .alpha.-naphthoic acid, .beta.-naphthoic acid,
tetrachlorophthalic acid and 2,2'-dicarboxydiphenyl.
Aromatic carboxylic acids of formula I wherein R.sub.1 or R.sub.5
is a hydroxyl group are defined by formula II, ##SPC2##
wherein R.sub.6 to R.sub.9 are as defined in R.sub.1 to R.sub.5 of
formula I.
Examples of such carboxylic acids include salicylic acid,
o-cresotinic acid, p-cresotinic acid, 3-ethylsalicylic acid,
4-ethylsalicylic acid, 3-isopropylsalicylic acid,
4-isopropylsalicylic acid, 5-isopropylsalicylic acid,
3-tert.-butylsalicylic acid, 5-tert.-butylsalicylic acid,
3-cyclohexylsalicylic acid, 5-cyclohexylsalicylic acid,
3-phenylsalicylic acid, 5-phenylsalicylic acid, 3-benzylsalicylic
acid, 5-tert.-octylsalicylic acid, 3-(.alpha.-methylbenzyl)
salicylic acid, 5-(.alpha.-methylbenzyl) salicylic acid, 5-nonyl
salicylic acid, 5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid,
5-chlorosalicylic acid, 5-butoxysalicylic acid and
5-octoxysalicylic acid.
Compounds of formula II wherein R.sub.6 and R.sub.8 are halogen,
alkyl, cycloalkyl, aryl, aralkyl or alkylaryl can be easily derived
in commercial scales from phenols, alkylphenols, arylphenols or
halogenated phenols. Examples of such aromatic carboxylic acids
include 3,5-dichlorosalicylic acid, 3-chloro-5-tert.-butylsalicylic
acid, 3-chloro-5-tert.-amylsalicylic acid,
3-chloro-5-tert.-octylsalicyclic acid,
3-chloro-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid,
3,5-dimethylsalicylic acid, 3-methyl-5-tert.-butylsalicylic acid,
3-methyl-5-cyclohexylsalicylic acid,
3-methyl-5-tert.-octylsalicylic acid,
3-methyl-5-(.alpha.-methylbenzyl) salicylic acid,
3-methyl-5-nonylsalicylic acid,
3-methyl-5-(.alpha.,.alpha.-dimethylbenzyl salicylic acid,
3,5-diisopropylsalicylic acid, 3,5-di-sec.-butylsalicylic acid,
3-tert.-butyl-5-chlorosalicylic acid,
3-tert.-butyl-5-methylsalicylic acid,
3-tert.-butyl-5-ethylsalicylic acid, 3,5-di-tert.-butylsalicylic
acid, 3-tert.-butyl-5-cyclohexylsalicylic acid,
3-tert.-butyl-5-phenylsalicylic acid, 3-tert.-butyl-5-(4'
-tert.-butylphenyl)salicylic acid, 3-tert.-amyl-5-chlorosalicylic
acid, 3-tert.-amyl-5-methylsalicylic acid,
3-tert.-amyl-5-ethylsalicylic acid, 3,5-di-tert.-amylsalicylic
acid, 3-tert.-amyl-5-cyclohexylsalicylic acid,
3-tert.-amyl-5-phenylsalicylic acid,
3-tert.-amyl-5-(4'-tert.-amylphenyl) salicylic acid,
3-cuclohexyl-5-chlorosalicylic acid, 3-cyclohexyl-5-methylsalicylic
acid, 3-cyclohexyl-5-ethylsalicylic acid, 3,5-dicyclohexylsalicylic
acid, 3-cyclohexyl-5-phenylsalicylic acid,
3-cyclohexyl-5-(4'-cyclohexylphenyl) salicylic acid,
3-phenyl-5-chlorosalicylic acid, 3-phenyl-5-isopropylsalicylic
acid, 3-phenyl-5-tert.-butylsalicylic acid,
3-phenyl-5-tert.-amylsalicylic acid, 3-phenyl-5-cyclohexylsalicylic
acid, 3-phenyl-5-benzylsalicylic acid,
3-phenyl-5-tert.-octylsalicylic acid,
3-phenyl-5-(.alpha.-methylbenzyl) salicylic acid,
3-phenyl-5-nonylsalicylic acid,
3-phenyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid,
3-benzyl-5-chlorosalicylic acid, 3-benzyl-5-methylsalicylic acid,
3-benzyl-5-ethylsalicylic acid, 3-benzyl-5-cyclohexylsalicylic
acid, 3-benzyl-5-phenylsalicylic acid, 3,5-dibenzylsalicylic acid,
3-benzyl-5-tert.-octylsalicylic acid, 3-benzyl-5-nonylsalicylic
acid, 3-benzyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid,
3-tert.-octyl-5-chlorosalicylic acid,
3-tert.-octyl-5-methylsalicylic acid,
3-tert.-octyl-5-ethylsalicylic acid,
3-tert.-octyl-5-cyclohexylsalicylic acid,
3-tert.-octyl-5-phenylsalicylic acid, 3,5-di-tert.-octylsalicylic
acid, 3-(.alpha.-methylbenzyl)-5-chlorosalicylic acid,
3-(.alpha.-methylbenzyl)-5-methylsalicylic acid,
3-(.alpha.-methylbenzyl)-5-ethylsalicylic acid,
3-(.alpha.-methylbenzyl)-5-cyclohexylsalicylic acid,
3-(.alpha.-methylbenzyl)- 5-phenylsalicylic acid,
3,5-di(.alpha.-methylbenzyl) salicylic acid,
3-(.alpha.-methylbenzyl)-5-(.alpha.,.alpha.-dimethylbenzyl)
salicylic acid, 3-(.alpha.-methylbenzyl)-
5-{4'-(.alpha.-methylbenzyl) phenyl} salicylic acid,
3-nonyl-5-chlorosalicylic acid, 3-nonyl-5-methylsalicylic acid,
3-nonyl-5-ethylsalicylic acid, 3-nonyl-5-phenylsalicylic acid,
3,5-dinonylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)-5-chlorosalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)-5-methylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)- 5-ethylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)- 5-t-amylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)- 5-cyclohexylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)- 5-phenylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)-5-(.alpha.-methylbenzyl)
salicylic acid, 3,5-di(.alpha.,.alpha.-dimethylbenzyl) salicylic
acid, 3-(4'-tert.-butylphenyl)-5-tert.-butylsalicylic acid,
3-(4'-cyclohexylphenyl)-5-cyclohexylsalicylic acid and
3-{4'-(.alpha.,.alpha.-dimethylbenzyl)
phenyl}-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid.
Aromatic carboxylic acids of formula II in which R.sub.7 or R.sub.9
is alkyl, cycloalkyl or phenyl can be derived from, for example,
metracresol, metapropylphenol, metaphenylphenol, 2,3-xylenol,
2,5-xylenol, 3,4-xylenol and 3,5-xylenol. Examples of such
carboxylic acids include 3,4-dimethylsalicylic acid,
4,5-dimethylsalicylic acid, 4,6-dimethylsalicylic acid,
4-methyl-5-isopropylsalicylic acid, 4-methyl-5-sec.-butylsalicylic
acid, 4-methyl-5-tert.-butylsalicylic acid,
4-methyl-5-tert.-amylsalicylic acid, 4-methyl-5-cyclohexylsalicylic
acid, 4-methyl-5-benzylsalicylic acid,
4-methyl-5-tert.-octylsalicylic acid,
4-methyl-5-(.alpha.-methylbenzyl) salicylic acid, 4-methyl-5
-nonylsalicylic acid, 4-methyl-5-(.alpha.,.alpha.-dimethylbenzyl)
salicylic acid, 3,6-dimethylsalicylic acid,
3-tert.-butyl-6-methylsalicylic acid, 3-tert.-amyl-
6-methylsalicylic acid, 3-cyclohexyl-6-methylsalicylic acid,
3-tert.-octyl-6-methylsalicylic acid,
3-(.alpha.-methylbenzyl)6-methylsalicylic acid,
3,6-diisopropylsalicylic acid, 3-tert.-butyl-6-isopropylsalicylic
acid, 3-tert.-octyl-6-isopropylsalicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)-6-isopropylsalicylic acid,
3-tert.-butyl- 6-phenylsalicylic acid,
3-tert.-amyl-6-phenylsalicylic acid, 3-cyclohexyl-6-phenylsalicylic
acid, 3-tert.-octyl-6-phenylsalicylic acid,
3-(.alpha.-methylbenzyl)-6-phenylsalicylic acid or
3-(.alpha.,.alpha.-dimethylbenzyl)-6-phenylsalicylic acid.
Aromatic carboxylic acids of formula II in which at least one of
R.sub.6 to R.sub.9 is a hydroxyl group are presented by formula
III, ##SPC3##
wherein R is an alkyl, cycloalkyl or aralkyl group, m is an integer
of 1 or 2 and n is an integer of 0 to 3. Examples of these
carboxylic acid include 3-hydroxysalicylic acid,
3-hydroxy-5-tert.-butylsalicylic acid,
3-hydroxy-5-tert.-amylsalicylic acid,
3-hydroxy-5-cyclohexylsalicylic acid,
3-hydroxy-5-tert.-octylsalicylic acid,
3-hydroxy-5-(.alpha.-methylbenzyl) salicylic acid, 3-hydroxy-
5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid,
3-hydroxy-4,6-dicyclohexylsalicylic acid, 4-hydroxysalicylic acid,
4-hydroxy-5-tert.-butylsalicylic acid, 4-hydroxy-5
-tert.-amylsalicylic acid, 4-hydroxy-5-cyclohexylsalicylic acid,
4-hydroxy-5-tert.-octylsalicylic acid,
4-hydroxy-5-(.alpha.-methylbenzyl) salicylic acid,
4-hydroxy-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid,
3,5-diisopropyl-6-hydroxysalicylic acid,
3,5-di-tert.-butyl-6-hydroxysalicylic acid,
3,5-di-tert.-amyl-6-hydroxysalicylic acid,
3,5-di-cyclohexyl-6-hydroxysalicylic acid,
3,5-di(.alpha.-methylbenzyl)-6-hydroxysalicylic acid,
3,5-di(.alpha.,.alpha.-dimethylbenzyl)-6-hydroxysalicylic acid,
5-hydroxysalicylic acid, 4-tert.-butyl-5-hydroxysalicylic acid,
4-tert.-amyl-5-hydroxysalicylic acid,
4-cyclohexyl-5-hydroxysalicylic acid,
4-(.alpha.-methylbenzyl)-5-hydroxysalicylic acid,
3,6-diisopropyl-5-hydroxysalicylic acid,
3,6-dicyclohexyl-5-hydroxysalicylic acid or
3,6-di(.alpha.-methylbenzyl)-5-hydroxy-salicylic acid.
As the case that any adjacent pair of R.sub.6 to R.sub.9 form a
ring together with the carbon atoms to which they are attached,
there are naphthalene derivatives. They are represented by formulae
IV, V and VI, ##SPC4## ##SPC5##
wherein R'.sub.1, R'.sub.2, R'.sub.3, R'.sub.4, R'.sub.5, R'.sub.6,
R'.sub.7 and R'.sub.8 each is hydrogen, halogen or a hydroxyl,
alkyl cycloalkyl or aralkyl group. As examples of such naphthalene
derivatives, there are indicated 1-hydroxy-2-carboxynaphthalene,
1-hydroxy-2-carboxy-4-isopropylnaphthalene,
1-hydroxy-2-carboxy-4-cyclohexylnaphthalene,
1-hydrogen-2-carboxy-4-benzylnaphthalene,
1-hydroxy-2-carboxy-4-(.alpha.-methylbenzyl) naphthalene,
1-hydroxy-2-carboxy-7-isopropylnaphthalene,
1-hydroxy-2-carboxy-7-tert.-butylnaphthalene,
1-hydroxy-2-carboxy-7-tert.-amylnaphthalene,
1-hydroxy-2-carboxy-7-cyclohexylnaphthalene,
1-hydroxy-2-carboxy-7-tert.-octylnaphthalene,
1-hydroxy-2-carboxy-7-(.alpha.-methylbenzyl) naphthalene,
1-hydroxy-2-carboxy-7-(.alpha.,.alpha.-dimethylbenzyl) naphthalene,
1-hydroxy-2-carboxy-4,7-diisopropylnaphthalene,
1-hydroxy-2-carboxy-4,7-di-tert.-butylnaphthalene,
1-hydroxy-2-carboxy-4,7-di-tert.-amylnaphthalene,
1-hydroxy-2-carboxy-4,7-dicyclohexylnaphthalene,
1-hydroxy-2-carboxy-4,7-di-benzylnaphthalene,
1-hydroxy-2-carboxy-4,7 -di-tert.-octylnaphthalene,
1-hydroxy-2-carboxy-4,7-di(.alpha.-methylbenzyl) naphthalene,
1-hydroxy-2 -carboxy-4,7-di(.alpha.,.alpha.-dimethylbenzyl)
naphthalene, 1-carboxy-2-hydroxy naphthalene,
1-carboxy-2-hydroxy-3,6,8-tri-tert.-butylnaphthalene,
2-hydroxy-3-carboxynaphthalene,
2-hydroxy-3-carboxy-6,8-di-tert.-butylnaphthalene,
2-hydroxy-3-carboxy-6,8-di-tert.-amylnaphthalene,
2-hydroxy-3-carboxy-6,8-dicyclohexylnaphthalene,
2-hydroxy-3-carboxy-6,8-di-tert.-octylnaphthalene,
2-hydroxy-3-carboxy-6,8-di(.alpha.-methylbenzyl) naphthalene or
2-hydroxy-3-carboxy-6,8-di(.alpha.,.alpha.-dimethylbenzyl)
naphthalene.
Aromatic carboxylic acids derived from, for example, bisphenol A,
4,4'-dihydroxycyclohexylidenebiphenyl,
4,4'-dihydroxymethylenebiphenyl and 2,2'-dihydroxydiphenyloxide are
regarded as condensates of salicylic acid. Examples of these
carboxylic acids include 5-(4'-hydroxybenzyl) salicylic acid,
5-(3'-carboxy-4'-hydroxybenzyl) salicylic acid
(methylene-bis-salicylic acid), 3-tert.-butyl-5-(3',5'
-di-tert.-butyl-4-hydroxybenzyl) salicylic acid,
3-(.alpha.,.alpha.-dimethylbenzyl)-5-{3',5'-di(.alpha.,.alpha.-dimethylben
zyl)-4'-hydroxybenzyl}salicylic acid,
3-tert.-butyl-5-(.alpha.,.alpha.-dimethyl-3',5'-di-tert.-butyl-4'-hydroxyb
enzyl) salicylic acid,
5-(.alpha.,.alpha.-dimethyl-3'-carboxy-4'-hydroxybenzyl) salicylic
acid, 5-(.alpha.,.alpha.-dimethyl-4'-hydroxybenzyl) salicylic acid,
3-(2'-hydroxyphenoxy) salicylic acid,
3-(2'-hydroxy-3'-carboxyphenoxy) salicylic acid,
3-(2'-hydroxy-3'-carboxy-5'-tert.-butylphenoxy)-
5-tert.-butylsalicylic acid,
3-(2'-hydroxy-3',5'-di-tert.-butylphenoxy)- 5-tert.-butylsalicylic
acid, 3-{2'-hydroxy-3'-carboxy-5'-(.alpha.,.alpha.-dimethylbenzyl)
phenoxy}-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid, 3-{
2'-hydroxy-3',5'-di(.alpha.,.alpha.-dimethylbenzyl)
phenoxy}-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid or
3-(2'-hydroxy-3',5'-dicyclohexylphenoxy)-5-cyclohexylsalicylic
acid.
Furthermore, a large number of aromatic carboxylic acids of formula
II which are difficult to be expressed in the chemical nomenclature
are listed. For instance, there are indicated condensation products
of formaldehyde with salicylic acid or nucleus-substituted
salicylic acids and phenols, salicylic acid or nucleus-substituted
salicylic acid adducts of propylene polymer or isobutylene polymer,
salicylic acid or nucleus-substituted salicylic acid adducts of
benzylchloride polycondensation products, salicylic acid or
nucleus-substituted salicylic acid adducts of styrene polymers,
salicylic acid or nucleus-substituted salicylic acid adducts of
.alpha.-methylstyrene polymers, salicylic acid or
nucleus-substituted salicylic acid condensates of aldehydes or
acetylene, salicylic acid or nucleus-salicylic acid condensate of
ketones, and salicylic acid or nucleus-substituted salicylic acid
adducts of compounds having an unsaturated bond.
The terms of "aromatic carboxylic acids" and "polyvalent metal
salts thereof" used herein and in the claims include also the
condensates and polymerizates as mentioned above and polyvalent
metal salts thereof.
All of the above aromatic carboxylic acids can form salts with
polyvalent metals.
Polyvalent metals which are concerned with the acceptors of the
present invention represent all the salt-forming metals other than
lithium, sodium, potassium, rubidium, cesium and francium. The
useful polyvalent metals include magnesium, aluminum, calcium,
scandium, titanium, vanadium, chromium, manganese, iron, cobalt,
nickel, copper, zinc, gallium, germanium, strontium, yttrium,
zirconium, niobium, molybdenum, silver, cadmium, indium, tin,
antimony, barium, tungsten, mercury, lead and bismuth. Further,
most suitable metals for the practical use of them are magnesium,
aluminum, calcium, titanium, manganese, zinc and tin.
Among the above-mentioned aromatic carboxylic acids and polyvalent
metal salts thereof, compounds having at least one hydroxyl group
on the benzene ring, particularly a hydroxyl group at the
ortho-position to the carboxyl group are preferred from the point
of view of color-forming ability. From aspects of the heat and
moisture resistances and the compatibility with an organic high
molecular compound, an aromatic carboxylic acid and polyvalent
metal salt thereof, having higher molecular weight are preferred,
that is, ones having 10 or more, preferably 17 or more carbon atoms
in total are recommended. Particularly, compounds of formulae II,
III, IV, V and VI in which 3 position to the carboxyl group is
substituted with isopropyl, secondary butyl, tert.-butyl,
tert.-amyl, cyclohexyl, phenyl, substituted phenyl, benzyl,
.alpha.-methylbenzyl, .alpha.,.alpha.-dimethylbenzyl, tert.-octyl,
nonyl and the other group having 3 or more carbon atoms show
excellent color-forming properties, stability toward water and
compatibility with an organic high molecular compound. Compounds of
formulae II, III, IV, V and VI bearing at least one 0 5-membered
and 6-membered carbon-rings as substituents and having 17 or more
carbon atoms in total are most preferred.
The polyvalent metal salts of aromatic carboxylic acid are obtained
by reaction of aromatic carboxylic acids with oxides, hydroxides,
carbonates and silicates of polyvalent metals, though they are
conveniently obtained by a double decomposition of an alkali metal
salt of aromatic carboxylic acid and a water soluble polyvalent
metal salt. In this case the aromatic carboxylic acid and water
soluble polyvalent metal salt each may be used alone or in mixture
of two or more. The polyvalent metal salts of aromatic carboxylic
acid are usually obtained in form of crystalline powders, amorphous
fine powders or viscous liquids.
An organic high molecular compound used in the invention should
show an easily non-fluidifying property at normal temperature and
preferably is selected from ones having a molecular weight of about
400 or more. The following are examples of useful organic high
molecular compounds: Polybutadiene, butadiene copolymers such as
butadiene-isoprene copolymer and butadiene-styrene copolymer,
cyclopentadiene polymers, cyclopentadiene copolymers, polystyrenes,
styrene copolymers, .alpha.-methylstyrene polymers,
.alpha.-methylstyrene copolymers, polyvinyl chloride, vinylchloride
copolymers, vinylidenechloride copolymers, polychloroprene
(Neoprene), acrylic ester polymers, acrylic ester copolymers,
acrylic acid copolymers, methacrylic ester polymers, methacrylic
ester copolymers, methacrylic acid copolymers, vinylacetate
polymers, vinylacetate copolymers such as ethylene-vinylacetate
copolymer, acrylonitrile copolymers, acrylamide copolymers,
allylalcohol copolymers, benzylchloride polycondensation products,
benzylchloride copolycondensation products,
meta-xylene-formaldehyde condensates, diphenyl-formaldehyde
condensates, diphenyl-meta-xylene-formaldehyde copolycondensation
products, phenol-formaldehyde condensates, substituted
phenol-formaldehyde condensates, phenol-meta-xylene-formaldehyde
condensates, the other phenol copolycondensation products, the
other substituted-phenol copolymers, polyester resins, melamine
resins, polycarbonate resins, butyral resins, nitrocellulose,
ethylcellulose, shellac, gilsonite, dammar. Styrene polymers,
styrene copolymers, .alpha.-methylstyrene polymers,
.alpha.-methylstyrene copolymers and substituted phenolformaldehyde
polymerization condensation products are preferred. These high
molecular compounds have good compatibility with various types of
the organic acid substance and therefore are easily pulverized to
fine powders, and maintain a good color-forming property.
It is desirable for the above mentioned organic high molecular
compound to be selected from compounds having compatibility with
the organic acid substance to be incorporated therein. The term of
"compatibility" used herein means such property that two or more
chemical substances dissolve with one another and also such
property that the dissolution occurs only in the one because of the
other being crystalline.
In many cases, the compatibility of a chemical substance may be
explained in relation with polarity of the substance. A suitable
combination of the organic acid substance and high molecular
compound in the present invention will be determined taking this
point of view into consideration. Generally speaking, the polarity
of chemical substance is qualitatively understood in the light of
the balance between an inorganophile and an organophile. An
aromatic carboxylic acid is usually increased in the organophile
and lowered in the polarity as the number of carbon atoms becomes
large. In the case of aromatic carboxylic acids having the same
number of carbon atoms, as polar radicals such as hydroxyl,
carboxyl, nitro, cyano, and halogen are introduced into the
molecule, the polarity becomes higher. The polarity may also vary
depending upon the type of radicals and the position of radicals in
the molecular. Types of polyvalent metals have influence on the
compatibility which may be explained in relation with the polarity.
For example, many of polyvalent metals which tend to form
polyvalent metal salts having a high inorganophile or high polarity
are metals with a relatively small atomic weight such as magnesium,
aluminum, calcium and titanium. To the contrary, zinc and tin tend
to form polyvalent metal salts with low inorganophile or low
polarity. On the other hand, in case of organic high molecular
compounds, when, for example, polyethylene and polypropylene which
are regarded as being of the lowest polarity are introduced with
double bond or substituted with halogen, benzene ring or hydroxyl,
carboxyl, ether, ester, ketone, nitro, cyano and amide radicals,
the polarity increases depending upon the type and number of the
substituents.
As substances having similar polarity are compatible or miscible
with each other, a pulverized homogeneous mixture comprising an
organic acid substance and organic high molecular compound is
obtained by selecting the organic high molecular compound having
the similar polarity to that of an aromatic carboxylic acid and
polyvalent metal salt.
An organic high molecular compound compatible with an organic acid
substance of a relatively high polarity is selected from one with a
high polarity which bears polar radicals in the molecule. However,
if such radicals as --C.ident.N, --CO--, --N=, --SO.sub.2 --,
--SO--, --S--, --PO=, --P=, --CS-- and --O-- are present in large
numbers in the molecule, they obstruct the color forming reaction
with a color former and therefore, it is desirable to confine the
introduction of such radicals to the irreducible minimum of a
demand. Halogen and a phenyl radical show no obstacle to the color
reaction. Particularly, hydroxyl and carboxyl radicals have no
obstacle to the color reaction and raise the polarity in the
presence of a small number of radicals.
Though an incorporation ratio of the organic high molecular
compound to the organic acid substance is not particularly limited,
when the amount of the former is too little, the desired resistance
toward heat, light and particularly a high moisture or water cannot
be attained. It is desirable to incorporate the organic high
molecular compound in the amount of 5 parts by dry weight or more,
preferably from 15 to 300 parts by weight based upon 100 parts by
dry weight of the organic acid substance.
There are many methods for obtaining a pulverized mixture
comprising the organic acid substance and organic high molecular
compound. For example, the most simple and preferable method
includes the steps of mixing and melting the organic high molecular
compound and organic acid substance while heating, solidifying the
resultant by cooling and then pulverizing it. Another method
includes the steps of dissolving the organic acid substance and
high molecular compound in an organic solvent therefor and mixing
same, evaporating the resultant to dryness and then pulverizing it.
The pulverizing may be effected in a dry system or in a wet system
with a medium such as water. In this case surface active agents and
fine powders with high hardness such as silicic anhydride and
kaolin may be allowed to co-exist in order to raise pulverization
efficiency.
As the organic high molecular compound used in the above described
methods, one having a relatively high glass transition point
(second order transition point) and a relatively low molecular
weight, is preferred. It is, in general said that an organic high
molecular compound having a large number of ring-structures in the
molecule shows a high second order transition point. There are, for
example, indicated polystyrene, styrene-.alpha.-methylstyrene
copolymers, .alpha.-methylstyrene polymers, cyclopentadiene
copolymers, aliphatic unsaturated cyclic hydrocarbon polymers,
benzylchloride-diphenyl poly-condensation products,
meta-xylene-formaldehyde poly-condensation product,
meta-xylene-diphenyl-formaldehyde copolycondensation products,
meta-xylene-alkylphenol-formaldehyde copoly-condensation products,
meta-xylene-diphenyl oxide-formaldehyde copoly-condensation
products, diphenyl-formaldehyde polycondensation products,
diphenyl-alkylphenol copoly-condensation products, substituted
phenol-formaldehyde poly-condensation products, substituted
phenol-diphenyl oxide-formaldehyde copoly-condensation products,
methacrylic ester polymers, acrylonitrilestyrene copolymers,
nitrocellulose, ethylcellulose, polyester resins and polycarbonate
resins, having a molecular weight of about 600 to 5000.
Alternatively, a particulate mixture in water dispersed form is
obtained by liquidizing the organic acid substance and high
molecular compound by heating or addition of an organic solvent,
dispersing in water the resultant, and cooling same or if
necessary, removing the organic solvent.
Further alternative method includes the steps of mixing the organic
acid substance and an initiator and regulator for polymerization
with a vinyl monomer capable of dissolving the organic acid
substance, such as styrene, .alpha.-methylstyrene, ethylacrylate
and methylmethacrylate, and effecting a suspension or emulsion
polymerization in water thereby to obtain a particulate mixture
consisting of the organic acid substance and organic high molecular
compound.
Furthermore, an alternative method for obtaining the particulate
mixture includes the steps of adding an alkali metal or ammonium
salt of aromatic carboxylic acids into an emulsion of organic high
molecular compounds, for example polystyrene emulsion and
styrene-butadiene copolymer emulsion, further adding an acid or an
aqueous solution of polyvalent metal salts thereto and effecting an
acid decomposition or double decomposition. In this case, heating
may be effected in order to promote the diffusion of the aromatic
carboxylic acid or polyvalent metal salt thereof into the particles
of the emulsified organic high molecular compound. A finely
pulverized mixture is thus obtained in the form of an emulsion or
dispersion in water.
In many cases, according to the invention, the organic acid
substance and organic high molecular compound completely dissolve
with each other and form a homogeneous phase, but even though
non-dissolving portions are in part present in the homogeneous
phase, it does not at all obstruct the objects of the invention.
The fine powders obtained are controlled to a particle size of
normally less than several microns, preferably about 0.5 .mu..
In some of the methods for preparation of the particulate mixture
comprising the organic acid substance and organic high molecular
compound, the particulate mixture may be further incorporated with
at least one of a water-insoluble inorganic material, in the form
of particles, such as oxides, hydroxides and carbonates of a metal,
and other mineral pigment, and an organic material in form of
powder such as powdered starch, powdered celluloses and organic
pigments. For example, in incorporating the organic acid substance
with the organic high molecular compound under heating, a
water-insoluble inorganic material in form of particles such as
clay, kaolin, activated clay, zinc oxide, calcium carbonate and
aluminum hydroxide is further incorporated therewith, solidified by
cooling and pulverized. Thus, a particulate substrate in which the
mixture of the organic acid substance and organic high molecular
compound is adsorbed around the inorganic powders is obtained. The
additional incorporation of the inorganic powders brings about
extending effect for the particulate substrate and improvement in
fluidity of coating composition. Particularly, the incorporation of
the inorganic powders, as mentioned hereinafter, improves a
color-forming property of the organic acid substance as well as
resistance of a sensitized sheet toward the sun light. An
incorporation amount of the inorganic or organic powders is not
particularly limited so far as the nature of the organic acid
substance does not recede. It is usually preferred to incorporate
the inorganic and/or organic powders in an amount of less than 2000
parts by dry weight based on 100 parts by dry weight of the organic
acid substance.
For the purposes of improving the compatibility between the organic
acid substance and organic high molecular compound and also the
color-forming property, it is preferred to further incorporate an
aliphatic carboxylic acid and/or polyvalent metal salt thereof into
the particulate substrate.
Examples of the aliphatic carboxylic acid include a saturated
monocarboxylic acid represented by the formula, C.sub.n H.sub.2n +
.sub.1 COOH wherein n is an integer, for example valeric acid,
caproic acid, caprylic acid, capric acid, lauric acid, myristic
acid, palmitic acid, stearic acid or a petrochemically derived
synthetic fatty acid, an unsaturated or cyclic mono-carboxylic acid
represented by the formula, C.sub.n H.sub.2n - .sub.m COOH wherein
n is an integer and m is an integer of 1, 3, 5, 7 or 9, for
example, acrylic acid, crotonic acid, oleic acid, elaidic acid,
erucic acid, linolic acid, linolenic acid, eleostearic acid,
phenylacetic acid or naphthylacetic acid, a mono-oxyfatty acid such
as lactic acid, ricinolic acid or oxystearic acid, a halogenated
fatty acid such as .alpha.-dichloropalmitic acid chlorostearic acid
and .alpha.,.alpha.-dichlorostearic acid, a poly-fattyacid such as
oxalic acid, malonic acid, succinic acid, glutaric acid, adipic
acid, suberic acid, azelaic acid, sebacic acid, maleic acid,
fumaric acid, itaconic acid, citraconic acid, mesaconic acid,
glutaconic acid, malic acid and citric acid, and halogenated
products thereof, phenoxyacetic acid, a nucleus substituted
phenoxyacetic acid, maleic acid copolymers, an unsaturated fatty
acid polymer or an unsaturated carboxylic acid copolymer, and
rosin.
A metal salt of the above aliphatic carboxylic acids may be also
used for the same purpose as mentioned above. These compounds
include salts of all the metals which can form the salts with the
above fattyacids. The aliphatic carboxylic acids and metal salts
thereof may be preferably used in an amount of less than about 100
parts by dry weight in respect of 100 parts by dry weight of the
organic acid substance and organic high molecular compound in
total.
A coating composition according to the invention is obtained by
dispersing the particulate mixture comprising the organic acid
substance and organic high molecular compound, if necessary, with a
suitable binder into water or a suitable organic solvent which does
not easily dissolve the organic acid substance and high molecular
compound. Such an organic solvent is exemplified by methanol,
ethanol, isopropanal, ethylene glycol and propylene glycol, and may
be used in mixture with water. Examples of the binder include
starch, casein, gelatine, gum arabic, polyvinyl alcohol,
polyacrylamide, acrylamide-methylol acrylamide copolymer,
acrylamide-acrylonitrile copolymer, methylolacrylamide-acrylic
ester copolymer, acrylamide-acrylic ester copolymer, acrylic
acid-acrylic ester copolymer, methyl cellulose, melamine resins,
urea resins, sodium polyacrylate, carboxymethyl cellulose,
carboxyethyl cellulose, natural rubber, synthetic rubber,
polyacrylic acid ester, polymethacrylic acid ester, polyvinyl
acetate, vinyl acetate-ethylene copolymer, polypropylene,
polystyrene, polyisobutylene, vinyl chloride-vinyl acetate
copolymer, methyl cellulose, ethyl cellulose, nitrocellulose,
cellulose acetate, phenol resins, butyral resins, petroleum resins
and alkyd resins.
The binders particularly water-soluble binders can be added with
chemical linking agents for forming water-insoluble binders by the
reaction.
If an aqueous coating composition is desired, a water insoluble
binder is used in the condition of suspension or emulsion in
water.
A carboxyl-modified polymer emulsion is particularly preferred
because it is quite stable in coatings and shows sufficient
adhesive property in a small quantity. Examples of such an emulsion
are carboxylated styrene-butadiene copolymer emulsion, carboxylated
methylmethacrylate-butadiene emulsion and vinyl acetate-crotonic
acid copolymer emulsion. In many cases the binders are used in a
mixture of two or more, and a suitable combination of water-soluble
and water-insoluble binders is usually used.
The coating composition of the invention may contain
water-insoluble oxides, hydroxide and carbonates of a metal and/or
other mineral pigments. Particularly such metal compounds as
oxides, hydroxides and carbonates of a polyvalent metal exhibit an
excellent color-forming property in co-existence with the aromatic
carboxylic acids. Therefore, these metal compounds are quite
effective to be used in combination with some of aromatic
carboxylic acids which are considered as disadvantageous in
practice because of an inactive color reaction and low color
density. Suitable inorganic metal compounds are oxides, hydroxides,
and carbonates of such a metal as magnesium, calcium, barium, zinc,
titanium, aluminum, nickel, cobalt, manganese, iron, tin, chromium,
and palladium, and for example, magnesium oxide, calcium oxide,
barium oxide, zinc oxide, aluminum oxide, tin oxide, magnesium
hydroxide, calcium hydroxide, zinc hydroxide, aluminum hydroxide,
tin hydroxide, magnesium carbonate, calcium carbonate and zinc
carbonate are particularly preferred.
The above inorganic metal compounds which generally belong to the
class referred to as "mineral pigments" have little color-forming
ability by themselves, but exhibit nevertheless the especial
color-forming ability in combination with the aromatic carboxylic
acids. The above specified metal compounds are, therefore, referred
to especially as "inorganic metal compounds" herein and
distinguished from the conventional mineral pigments. The mineral
pigments other than the inorganic metal compounds to be used are
exemplified by activated clay, acid clay, aluminum silicate, zinc
silicate, tin silicate, a colloidal aluminum hydrosilicate zeolite,
bentonite, kaolin and talc. They are referred to merely as "mineral
pigment" in the invention.
The coating composition may include the above defined inorganic
metal compound and mineral pigment in an amount of 1 to 10,000,
preferably 5 to 1,000 parts by dry weight in respect of 100 parts
by dry weight of the aromatic carboxylic acid and/or polyvalent
metal salt thereof. It should be understood that the coating
composition may contain all or a part of the inorganic metal
compound and mineral pigment incorporated in the particulate
substrate comprising the organic acid substance and organic high
molecular compound as mentioned hereinbefore.
The desired coating compositions for some types of self-contained
copying papers contain further fine capsules enveloping the color
former therein.
The coating composition is applied on the surface of a support by
the conventional coating means, for example an air knife, rolls,
blades and a sizing press or said composition is printed on the
support by the printing press, for example a letter press and
flexographic method. If a coating composition is of an organic
solvent type, the printing method is preferred and the coating
composition may contain further a plasticizer such as tributyl
phosphate, dibutyl phthalate, dioctyl phthalate, butyl adipate and
castor oil.
A paper of natural fibers, a paper of synthetic fibers and a film
of synthetic polymers may be used as the support, though the paper
of natural fibers is usually used. The support, if necessary, may
be one having a barrier-coat of a natural or synthetic high
molecular substance.
The sensitized sheet according to the invention has advantages as
described hereunder. The organic acid substance, because of being
prevented from the actions of heat, light and particularly high
moisture or water by the organic high molecular compound, can
maintain a stable color-forming ability for a long time and
completely prevent the "smudge". Accordingly, an organic acid
substance with a relatively low molecular weight such as salicylic
acid or its polyvalent metal salt which was unsuitable for
practical use can be now put to practical use.
The coating composition, because of being excellent in mechanical
and thermal stability, can be preserved in a state of perfection
and also the coating work can be easily effected. Further, it is
possible to apply it on the support by a coating apparatus mounted
on the paper machine so that the pressure sensitive recording
sheets are obtained in extremely economical way.
The particular mixture comprising the organic acid substance and
organic high molecular compound can be pulverized to fine powders
with an uniform particle size of several microns by the mechanical
means, for example ball milling. It is, therefore, possible to form
a coating layer in which the fine powders are homogeneously
dispersed so that clear images free of bleeding are obtained.
The coating composition is usually applied in an amount of more
than about 2g/m.sup.2 and the upper limit is confined by a mere
economical reason.
The invention is illustrated by non-limitative Examples to follow.
Amounts of formulation are given in parts by dry weight unless
otherwise indicated.
EXAMPLE 1
100 parts of a thermoplastic modified xylene resin with a softening
point of 110.degree. C (solid as Nikanol S-100 by Mitsubishi Gas
Chemistry Co., Japan) were heated to 180.degree.20C, added with 90
parts of zinc 3,5-di(.alpha.,.alpha. -dimethylbenzyl) salicylate
while stirring, and dissolved. A mass was obtained by cooling and
solidifying the mixture. The mass was coarsely crushed and then
pulverized with 200 parts of kaolin and 30 parts of a powdered
silicic anhydride (sold as Carplex No. 80 by Shionogi
Pharmaceutical Co., Japan) in a ball mill for 15 hours. A
particulate mixture with an average particle size of about 3 .mu.
were, thus, obtained. The total contents of the ball mill were
added with 40 parts of a soluble starch and 100 parts of
styrene-butadiene copolymerization latex (solids, 50 %) to 600
parts of water and stirred thoroughly. A coating composition was,
thus, obtained. A sensitized sheet was obtained by applying the
coating composition on the surface of a continuously running paper
web of 50g/m.sup.2 in an amount of 10g/m.sup.2 by dry weight, using
a pilot paper machine (sold as RISSAR PAPER MACHINE by Mitsubishi
Kakoki Co. Japan) provided with the similar coater to a commercial
coater in large scale.
The coating composition was applied on the surface of a preheated
paper web and recycled during the coating work. As the result the
coating composition was subject to mechanical shearing and
concurrently reached the temperature of 70.degree.C at the highest,
but maintained a markedly stable fluidity without increase of
viscosity.
EXAMPLE 2-1 .about. 2-14
100 parts of .alpha.-methylstyrene-styrene copolymer with a
molecular weight of about 1500 obtained by polymerization of 60
wt.% of .alpha.-methylstyrene and 40 wt.% of styrene in the
presence of thioglycolic acid were incorporated into and melted
with 200 parts of each of organic acid substances as given
hereunder at temperatures of 150.degree. to 190.degree.C to form a
homogeneous liquid phase. An easily crushable mass was obtained by
cooling the liquid phase.
______________________________________ Example No. Organic acid
substances ______________________________________ 2-1
3,5-di-(.alpha.-methylbenzyl) salicylic acid 2-2 Zinc
3-phenyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylate 2-3 Aluminum
3-phenyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylate 2-4 Zinc
3-cyclohexyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylate 2-5 Zinc
salt of 3-cyclohexyl-5-(.alpha.,.alpha.- dimethylbenzyl) salicylic
acid 70 weight % and its aluminum salt 30 weight % 2-6 Zinc
3,5-di-(.alpha.,.alpha.-dimethylbenzyl) salicylate 2-7 Zinc salt of
3,5-di-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid 70 weight %
and its aluminum salt 30 weight % 2-8 Zinc
3-(.alpha.-methylbenzyl)-5-(.alpha.,.alpha.-dimethylbenzyl)
salicylate 2-9 Zinc salt of
3-(.alpha.-methylbenzyl)-5-(.alpha.,.alpha.- dimethylbenzyl)
salicylic acid 70 weight % and its aluminum salt 30 weight % 2-10
Zinc 3,5-di-(.alpha.,.alpha.-dimethylbenzyl) salicylate 2-11 Zinc
3-(.alpha.,.alpha.-dimethylbenzyl)-5-phenyl salicylate 2-12
Aluminum 3-(.alpha.,.alpha.-dimethylbenzyl)-5-phenyl salicylate
2-13 Zinc salt of 3-(.alpha.,.alpha.-dimethylbenzyl)-5- phenyl
salicylic acid 70 weight % and its aluminum salt 30 weight % 2-14
Zinc 3,5-dicyclohexyl salicylate
______________________________________
200 parts of each of the mass thus obtained were crushed to an
average particle size of about 200 .mu., incorporated with one part
of a formaldehyde-sodium naphthalenesulfonate condensate (sold as
Demol-N by Kao Atlas Co. Japan), 600 parts of water and 20 parts of
a soluble starch, and then passed through a sand grind mill.
Finally, 40 parts of a styrene-butadiene copolymerization latex
(solids, 50%) were added thereto to obtain various coating
compositions.
Sensitized sheets were obtained by applying each of the coating
compositions on a support in an amount of 7g/m.sup.2 by dry weight
in the same manner as in Example 1. All of the coating compositions
exhibited an excellent mechanical and thermal stability during the
coating work.
EXAMPLE 3-1 .about. 3-14
200 parts of each of the mass obtained in Example 2 were crushed to
an average particle size of about 200 .mu., incorporated with 200
parts of kaolin, 50 parts of zinc oxide, 600 parts of water, 40
parts of a soluble starch and one part of Demol-N (see Example 2),
and then pulverized in a sand grind mill. Finally, 100 parts of a
carboxylated styrene-butadiene copolymerization latex (solids, 50%)
were added thereto the obtained various coating compositions.
Sensitized sheets were obtained by applying each of the coating
compositions on a support in an amount of 10g/m.sup.2 by dry weight
in the same manner as in Example 1. All of the coating composition
exhibited the same mechanical and thermal stability as in Example
1.
EXAMPLE 4
A coating composition was obtained in the same procedure as in
Example 1 except that 5 parts of zinc stearate were further added
in the incorporation of 100 parts of Nikanol S-100 and 90 parts of
zinc 3,5-di(.alpha.,.alpha.-dimethylbenzyl) salicylate.
A sensitized sheet was obtained from the coating composition in the
same manner as in Example 1.
EXAMPLE 5
100 parts of .alpha.-methylstyrene polymer with a molecular weight
of about 1100 were heated at about 180.degree.C together with 10
parts of zinc stearate and 60 parts of zinc 3-{4'-(.alpha.,.alpha.
-dimethylbenzyl) phenyl} -5-(.alpha.,.alpha. -dimethylbenzyl)
salicylate, melted and incorporated in. The resultant was cooled,
solidified and coarsely crushed. All of the crushed products were
incorporated with 40 parts of a powdered zinc silicate, 20 parts of
polyacrylamide (degree of polymerization, about 1000) and 500 parts
of water and pulverized in a porcelain ball mill for about 20
hours. Finally, 60 parts of a styrene-butadiene polymerization
latex were added thereto to form a coating composition.
A sensitized sheet was obtained from the coating composition in the
same procedure as in Example 1. The coating composition exhibited a
good mechanical and thermal stability during the coating work.
EXAMPLE 6-1 .about. 6-14
100 parts of a novolak type p-phenylphenolformaldehyde
polycondensation product (molecular weight, about 800) were
incorporated into and melted with 150 parts of each of the organic
acid substances as indicated hereunder at temperatures of
100.degree. .about. 200.degree.C. A mass was obtained by cooling
and solidifying the resulting liquid.
______________________________________ Example No. Organic acid
substances ______________________________________ 6-1 Salicylic
acid 6-2 Zinc salicylate 6-3
3-hydroxy-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid 6-4
Zinc 3-hydroxy-5-(.alpha.,.alpha.-dimethylbenzyl) salicylate 6-5
Zinc 3-phenyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylate 6-6
Zinc, 3,5-di(.alpha.-methylbenzyl) salicylate 6-7 Zinc
3,5-di-tertiary-butyl salicylate 6-8 Zinc 4-octoxylbenzoate 6-9
Zinc 3-phenyl salicylate 6-10 4-tertiary-butylbenzoic acid 6-11
Zinc 5-(3'-carboxy-4'-hydroxybenzyl) salicylate 6-12
5-(3'-carboxy-4'-hydroxybenzyl) salicylic acid 6-13 Magnesium
3,5-di-tertiary-butyl-salicylate 6-14
1-carboxy-2,3-dihydroxy-6-(.alpha.,.alpha.- dimethylbenzyl)
naphthalene 50 weight % and
1-carboxy-2,3-dihydroxy-7-(.alpha.,.alpha.- dimethylbenzyl)
naphthalene 50 weight % ______________________________________
Each of the mass was crushed to powders with a particle size of
about 200 .mu.. 200 parts of each of the powdered substances were
incorporated with 50 parts of zinc oxide, 600 parts of water and 40
parts of a soluble starch and pulverized in a sand grind mill.
Finally, 100 parts of a carboxylated styrene-butadiene copolymer
latex (solids, 50%) were added to form a coating composition. A
sensitized sheet was obtained by applying the coating composition
on a support in the same manner as in Example 1. Each of the
coating compositions exhibited the same mechanical and thermal
stability as that of Example 1.
EXAMPLE 7
100 parts of polystyrene with a molecular weight of about 1000, 50
parts of aluminum 3-(.alpha.,.alpha.-dimethylbenzyl)
-5-cyclohexylsalicylate and 300 parts of kaolin were heated at
180.degree.C, melted and incorporated in. A mass was obtained by
cooling and solidifying the resultant. The mass was coarsely
crushed, then incorporated with 520 parts of an aqueous solution
containing 20 parts of polyvinyl alcohol and pulverized in a ball
mill for 20 hours. Finally, 20 parts of a styrene-butadiene
copolymer latex (solids, 50%) were added to form a coating
composition.
A sensitized sheet was obtained from the coating composition in the
same procedure as in Example 1. The coating composition exhibited
the same mechanical and thermal stability as that of Example 1.
EXAMPLE 8
100 parts of .alpha.-methylstyrene polymer with a molecular weight
of about 1000, 50 parts of
3-cyclohexyl-5-(.alpha.,.alpha.-dimethylbenzyl) salicylic acid, 3
parts of stearic acid and 30 parts of zinc oxide were heated at
170.degree.C, melted and incorporated in. The resultant was cooled
and solidified to form a mass. The mass obtained was coarsely
crushed, added with 500 parts of an aqueous solution containing 20
parts of starch and then pulverized in a ball mill for 10 hours.
Finally, 50 parts of a styrene-butadiene copolymer latex (solids,
50%) were added to form a coating composition.
A sensitized sheet was obtained from the coating composition in the
same procedure as in Example 1. The coating composition exhibited
the same mechanical and thermal stability as that of Example 1.
EXAMPLE 9
100 parts of polystyrene with a molecular weight of about 2000
obtained by a polymerization in carbon tetrachloride and 100 parts
of aluminum 3,5-di(.alpha.-methylbenzyl) salicylate were
incorporated and melted at about 150.degree.C, then cooled and
solidified. The mass obtained was crushed to granules with a
particle size of less than about 1000 .mu., added with 400 parts of
kaolin and 100 parts of zinc oxide, and pulverized in a ball mill
for 10 hours. All of the milled products were dispersed in a
solution consisting of 200 parts of water, 800 parts of ethanol and
100 parts of ethylcellulose to form an ink composition.
A sensitized sheet was obtained by printing the ink composition on
a support with a weight of 50 g/m.sup.2 in an amount of 7 g/m.sup.2
by dry weight using the usual printing machine.
EXAMPLE 10
100 parts of a styrene allylalcohol copolymer (monomer weight ratio
90 : 10, molecular weight about 3,000) and 200 parts of zinc
3,5-di-(.alpha.-methylbenzyl) salicylate were dissolved in 200
parts of acetone. The acetone was, then, evaporated to obtain a
mass. The mass was coarsely crushed to a particle size of about 200
.mu., and 200 parts of the crushed products were incorporated with
1 part of Demol-N (see Example 2), 600 parts of water and 20 parts
of a soluble starch and pulverized in a grinder (sold as Attritor
by Mitsui Miike Seisakusho, Japan). Finally, 40 parts of
styrene-butadiene copolymer latex (solids, 50%) were added to form
a coating composition.
A sensitized sheet was obtained with use of the coating composition
in the same manner as in Example 1.
EXAMPLE 11
100 parts of a styrene-allylalcohol copolymer (monomer weight ratio
85 : 15, molecular weight about 1500) and 300 parts of zinc
3,5-di-(.alpha.-methylbenzyl) salicylate were dissolved in 300
parts of acetone. The solution obtained thus was little by little
added to a dispersion consisting of 2500 parts of water, 30 parts
of Demol-N and 500 parts of kaolin while stirring whereby a
dispersion of a particulate substrate consisting of the
styrene-allylalcohol copolymer and zinc
3,5-di-(.alpha.-methylbenzyl) salicylate was obtained. A sensitized
sheet was obtained by applying the dispersion on a support of 50
g/m.sup.2 in weight in an amount of 7 g/m.sup.2 by dry weight.
EXAMPLE 12
To 200 parts of a polystyrene emulsion (solids, 50%) were added 100
parts of a 30% aqueous solution of sodium
3-(.alpha.,.alpha.-dimethylbenzyl)-5-methyl salicylate, heated to a
temperature of 80.degree.C and added little by little with 500
parts of a 40% aqueous solution of stannous chloride while
stirring. Thereafter, stirring was further effected for about one
hour while maintaining a temperature the solution at 90.degree.C.
The emulsified polystyrene particles obtained herein contain tin
3-(.alpha.,.alpha.-dimethylbenzyl)-5-salicylate. Next, 150 parts of
kaolin, 100 parts of water and 30 parts of a soluble starch were
added to the above emulsion while vigorously stirring whereby a
coating composition was obtained.
A sensitized sheet was obtained with use of the coating composition
in the same procedure as in Example 1.
EXAMPLE 13-1 .about. 13-9
100 parts of zinc 3,5-di(.alpha.-methylbenzyl) salicylate were
incorporated in and melted with 50 parts of each of the organic
high molecular compounds as indicated hereunder. The resultant was
cooled and solidified, thus a mass being obtained.
______________________________________ Example No. Organic high
molecular compounds ______________________________________ 13-1
Styrene-.alpha.-methylstyrene copolymer (monomer weight ratio 60 :
40, molecular weight 5,000) 13-2 Polystyrene (molecular weight
1,500) 13-3 Styrene-acrylonitrile copolymer (monomer weight ratio
80 : 20, molecular weight 2,000) 13-4 Vinylchloride-vinylacetate
copolymer (monomer weight ratio 85 : 15, molecular weight 5,000)
13-5 Styrene-methylmethacrylate copolymer (monomer weight ratio 80
: 20, molecular weight 2,000) 13-6 Diphenyl-formaldehyde
polycondensation product (molecular weight 600) 13-7 Shellac 13-8
Polystyrene (molecular weight 1,500) 70 weight % and
paraoctylphenol- formaldehyde polycondensation product (molecular
weight 800) 30 weight % 13-9 Paraphenylphenol-formaldehyde
polycondensation product (molecular weight 700) 60 weight % and
isophthalic acid- ethylene glycol polycondensation product
(molecular weight 1,800) 40 weight %
______________________________________
______________________________________ Example No. Organic high
molecular compounds ______________________________________ 13-1
Styrene-.alpha.-methylstyrene copolymer (monomer weight ratio 60 :
40, molecular weight 5,000) 13-2 Polystyrene (molecular weight
1,500) 13-3 Styrene-acrylonitrile copolymer (monomer weight ratio
80 : 20, molecular weight 2,000) 13-4 Vinylchloride-vinylacetate
copolymer (monomer weight ratio 85 : 15, molecular weight 5,000)
13-5 Styrene-methylmethacrylate copolymer (monomer weight ratio 80
: 20, molecular weight 2,000) 13-6 Diphenyl-formaldehyde
polycondensation product (molecular weight 600) 13-7 Shellac 13-8
Polystyrene (molecular weight 1,500) 70 weight % and
paraoctylphenol- formaldehyde polycondensation product (molecular
weight 800) 30 weight % 13-9 Paraphenylphenol-formaldehyde
polycondensation product (molecular weight 700) 60 weight % and
isophthalic acid- ethylene glycol polycondensation product
(molecular weight 1,800) 40 weight %
______________________________________
Each of the above mass was coarsely crushed. 150 parts of each of
the crushed products were incorporated with 75 parts of kaolin, 35
parts of activated clay, 450 parts of water and 30 parts of a
soluble starch and pulverized in a sand grind mill. Finally, 75
parts of a styrene-butadiene copolymer latex (solids, 50%) were
added to form a coating composition. A sensitized sheet was
obtained from the coating composition in the same procedure as in
Example 1. The coating composition exhibited a good mechanical and
thermal stability like Example 1.
For comparison with the above Examples an aqueous dispersion of
organic acid substance containing the composition as indicated
hereunder was prepared separately.
______________________________________ Control 1 : Composition
Parts by weight ______________________________________ Salicylic
acid 100 Demol-N (see Example 2) 1 Polyvinyl alcohol 5 Control 2 :
Composition Parts by weight ______________________________________
Salicylic acid 100 Zinc oxide 300 Demol-N 4 Polyvinyl alcohol 20
Control 3 : Composition Parts by weight
______________________________________ Zinc 3-phenylsalicylate 100
Demol-N 1 Styrene-butadiene copolymer Latex (solids 50%) 16 Control
4 : Composition Parts by weight
______________________________________ Zinc 3,5-di-tertiary-butyl
salicylate 100 Activated clay 300 Demol-N 4 Starch 9
Styrene-butadiene copolymer Latex (solids 50%) 56
______________________________________
A sensitized sheet was obtained by applying each of the above
dispersion on a support of 50 g/m.sup.2 in weight in an amount of 7
to 10 g/m.sup.2 by dry weight according to the same procedure as in
Example 1.
For confirming effects of the sensitized sheets of the invention,
an upper sheet coated with micro-capsules enveloping a color former
therein was prepared. The micro-capsules may be prepared in
accordance with, for example, U.S. Pat. No. 2,800,457. An
embodiment for the preparation is given hereunder.
30 parts of an acid treated gelatin were added to 470 parts of
water and dissolved at 60.degree.C. 3 parts of Crystal Violet
Lactone were dissolved in 100 parts of isopropylnaphthalene, warmed
at 60.degree.C, and added with the above obtained aqueous solution
of gelatin, which were then emulsified and dispersed with stirring
to form oil droplets with an average particle size of 4 to 5 .mu..
Next, 300 parts of a 10% aqueous solution of gum arabic were added
to the above emulsion, further added with 200 parts of water, and
thereafter a pH of the dispersion was adjusted to the range of 4 to
4.5 by adding acetic acid. The dispersion was cooled to 10.degree.C
to allow a coacervate film to gel and added with 10 parts of
formaldehyde. After ageing for 10 hours a capsule dispersion was
formed. An upper sheet was obtained by applying the dispersion on a
support paper of 50 g/m.sup.2 in weight in an amount of 5 g/m.sup.2
by dry weight.
Effects of the sensitized sheets of the invention were confirmed by
the manners to follow. A sensitized sheet subjected to the
treatments as mentioned hereunder and a sensitized sheet not
subjected respective were placed under an upper sheet carrying the
encapsulated color former in such a way that the coated surface is
in contact with the micro-capsules, and a marking pressure by means
of a typewriter was applied. Stabilities of color-forming ability
toward heat, light and moisture were observed by differences in
density of a developed color image between the treated and
untreated sheets
a. Allowing a sensitized sheet to stand in surroundings of a 90%
relative humidity and temperature of 50.degree.C for 10 hours.
b. Allowing a sensitized sheet to stand in surroundings of
100.degree.C in a temperature for 5 hours.
c. Exposing a sensitized sheet direct to the sun for 3 hours.
Apart from the above tests, a sensitized sheet was brought into
close contact with an upper sheet in such a way that the coated
surface and the micro-capsules are opposite to each other. After
dipping in water the set of sheets was dried and separated to each.
In case a sensitized sheet has low resistance toward water, the
coated surface of the upper sheet forms a color and thus there
arises the "smidge".
The results of the above mentioned tests are given in Table 1.
For confirming stabilities of a developed color image toward light,
heat, moisture and water, the following tests were made. The upper
sheet was placed over the sensitized sheet in such a way that the
coated surface and the micro-capsules are opposite to each other,
and a marking pressure by means of a typewriter was applied. After
standing for 24 hours the sensitized sheet was subject to the
treatments to follow and a lowering in density of the color image
was observed.
a. Allowing a sensitized sheet to stand in surroundings of a 90%
relative humidity and 50.degree.C in a temperature for 10
hours.
b. Allowing a sensitized sheet to stand in surroundings of
100.degree.C in a temperature for 5 hours.
c. Exposing a sensitized sheet direct to the sun for 3 hours.
d. Dipping a sensitized sheet in water and drying at normal
temperature.
The results of the above tests are given in Table 1.
Table 1
__________________________________________________________________________
Stability of Stability of Color-forming Ability Developed Color
Image Example Mois- Ther- Mois- Ther- Color No. ture mal Light
Water ture mal Light Water Intensity Resis- Resis- Resis- Resis-
Resis- Resis- Resis- Resis- of the tance tance tance tance tance
tance tance tance Image
__________________________________________________________________________
1 B A A A B A B B A 2-1 B A A A B A B B C 2-2 B A A A B A B B A 2-3
B A B A B A B B B 2-4 B A A A B A B B A 2-5 B A B A B A B B B 2-6 B
A A A B A B B A 2-7 B A B A B A B B B 2-8 B A A A B A B B A 2-9 B A
B A B A B B B 2-10 B A A A B A B B A 2-11 B A A A B A B B A 2-12 B
A B A B A B B B 2-13 B A B A B A B B B 2-14 B A A A B A B B A 3-1 A
A A A A A B B B 3-2 A A A A A A B B A 3-3 A A B A A A B B B 3-4 A A
A A A A B B A 3-5 A A B A A A B B B 3-6 A A A A A A B B A 3-7 A A B
A A A B B B 3-8 A A A A A A B B A 3-9 A A B A A A B B B 3-10 A A A
A A A B B A 3-11 A A A A A A B B A 3-12 A A B A A A B B B 3-13 A A
B A A A B B B 3-14 A A A A A A B B A 4 B A B A A A B A A 5 B A B A
A A B A A 6-1 B A A A B A B A B 6-2 A A A A B A B A A 6-3 B A A A B
A B A B 6-4 A A A A B A B A A 6-5 A A A A B A B A A 6-6 A A A A B A
B A A 6-7 A A A A B A B A A 6-8 A A A A B A B A A 6-9 A A A A B A B
A A 6-10 B A A A B A B A B 6-11 A A A A B A B A A 6-12 B A A A B A
B A B 6-13 A A A A B A B A A 6-14 B A A A B A B A B 7 B A B A A A B
A B 8 B A A A A A A A B 9 B A A A B A B A B 10 B A B B B A B A A 11
B A A A B A B A A 12 B A A B B A A B B 13-1 B A A A B A B B A 13-2
A A B A A A B A A 13-3 A A B A A A B A A 13-4 B B B A B B B A B
13-5 B A A A B A A B A 13-6 B A A A B A B A A 13-7 A A B A A A B A
A 13-8 B A A A B A B B A 13-9 B A A A B A A B A Control 1 C B B D C
B B D C 2 C A B D C A B D B 3 C A B D C A B D A 4 C A B B C A C B A
__________________________________________________________________________
Stability of color-forming ability A: maintained its original
color-forming ability B: scarcely deteriorated C: remarkably
deteriorated D: entirely deteriorated (color images could not be
formed) Stability of developed color image A: not changed in color
at all B: scarcely faded C: remarkably faded D: faded or discolored
Color intensity of the image A: high B: average C: extremely
low
* * * * *